Well, the distance from the closet dealer definitely will play a hand in your choice. There are definitely more Lutron dealers out there. Actually one of the reasons I became a Vantage Dealer. Both great products but much less competition.
For the record I do not know nearly as much about Homeworks as I do Vantage.
Vantage Infusion
Lighting and Home Automation Platform - Controls their own Lighting products, as well as other manufacturers Shading, Audio, Video, HVAC, and other electronic products via IR, RS-232, and IP.
Lighting Modules can be changed without the need for an Electrician (which is great for an integrator without an electrical license like myself - saves money and time for integrator and home owner).
Wiring for the low voltage switches is incredibly easy.
Some of their keypads have multicolor LEDs that let the installer/programmer do some unique things with them, such as brightness of LED being able to indicate a different scene being active or how bright the lights are or having the light change colors when turned on, off, etc.
Vantage RF wireless system has a 100ft radius. That's 100ft in every direction.
Equinox single gang 4" glass touchscreen is a great addition to (or replacement for the) keypads to control the lighting, shading, HVAC (or outside temp), and Music. They look amazing. They have a feature where you can program a scene or function to activate by just waving your hand in front of it. Great for turning the lights on when entering the room. and a hard button you could use to turn it off or whatever else you'd like.
Equinox 7" glass touchscreen adds other functionality like controlling and viewing cameras, controlling TVs and surround sound, full audio system control, etc.
Future Equinox 4" touchscreen will have similar functionality as the 7". Check out the Equinox on Vantage's website.
You can use 3rd Party (as well as Vantage's) sensors for functionality. Such as Light sensors, temp sensors, vacancy/occupancy sensors, door sensors, etc to automatically activate lights, scenes, or use them to change the scenes that you have programmed into keypad buttons. Basically do whatever you want.
Lutron Homeworks
Lighting, shading, and Hvac products. Cannot (as far as i know) control 3rd party products. You are basically stuck using all Lutron (which isn't necessarily a bad thing, just limiting.)
Lutron has better integration with Home Control systems. Vantage has integration with control systems as well, but Lutron definitely has leg up there.
Lutron definitely has a wider array of color options for their keypads than Vantage, but both have the main ones, as well as a number of others.
Not sure if Lutron's keypads have the multicolor LED option (doesn't seem like a big deal, but it's kind of cool what you can do with them (as well as a designers dream to customize)
Wireless system only has a 30ft radius which means a better chance that a 2nd and 3rd (or more if capable) wireless repeater will be necessary in a large home.
Lutron Does NOT have anything like the Equinox Touchscreens.
I'm not sure if you can use 3rd party sensors directly with Lutron Homeworks. That you would need to ask a Homeworks dealer.
Changing out Modules requires electrician. Wires need to be disconnected to remove module. (Vantage just requires flipping circuit breaker off then back on.)
Basically, both products are pretty bullet proof. Both have similar features. When I was at Vantage training a guy there who had been programming Lutron Homeworks for years said that the Homeworks programming platform was easier to program with, but the Vantage platform was more powerful and flexible (then on top of that it can also control other products that Homeworks cannot.)
I'm hoping a Homeworks dealer will chip in with some features/benefits of that system! Then I may be able to compare to Vantage.